Effect of a carbon reinforcement for maximizing shoe outsole bending stiffness on plantar pressure and walking comfort in people with diabetes at high risk of foot ulceration

Changes in Dynamic Mean Ankle Moment Arm in Unimpaired Walking Across Speeds, Ramps, and Stairs

Understanding the natural biomechanics of walking at different speeds and activities is crucial to develop effective assistive devices for persons with lower-limb impairments. While continuous measures such as joint angle and moment are well-suited for biomimetic control of robotic systems, whole-stride summary metrics are useful for describing changes across behaviors and for designing and controlling passive and semi-active devices. Dynamic mean ankle moment arm (DMAMA) is a whole-stride measure representing the moment arm of the ground reaction impulse about the ankle joint-effectively, how "forefoot-dominated" or "hindfoot-dominated" a movement is. DMAMA was developed as a target and performance metric for semi-active devices that adjust once per stride. However, for implementation in this application, DMAMA must be characterized across various activities in unimpaired individuals. In our study, unimpaired participants walked at "slow," "normal," and "fast" self-selected speeds on level ground and at a normal self-selected speed while ascending and descending stairs and a 5-degree incline ramp. DMAMA measured from these activities displayed a borderline-significant negative sensitivity to walking speed, a significant positive sensitivity to ground incline, and a significant decrease when ascending stairs compared to descending. The data suggested a nonlinear relationship between DMAMA and walking speed; half of the participants had the highest average DMAMA at their "normal" speed. Our findings suggest that DMAMA varies substantially across activities, and thus, matching DMAMA could be a valuable metric to consider when designing biomimetic assistive lower-limb devices.

Pressure-Relieving Effect of Different Insole Top Covers in People with Diabetes at High Risk of Foot Ulceration

Pressure-relieving footwear helps prevent foot ulcers in people with diabetes. The footwear design contributes to this effect and includes the insole top cover. We aimed to assess the offloading effect of materials commonly used as insole top cover. We measured 20 participants with diabetes and peripheral neuropathy for in-shoe peak pressures while walking in their prescribed footwear with the insole covered with eight different materials, tested in randomized order. Top covers were a 3 mm or 6 mm thick open or closed-cell foam or a 6 mm thick combination of open- and closed-cell foams. We re-assessed pressures after one month of using the top cover. Peak pressures were assessed per anatomical foot region and a region of interest (i.e., previous ulceration or high barefoot pressure). Walking comfort was assessed using a 10-point Likert scale. Mean peak pressure at the region of interest varied between 167 (SD:56) and 186 (SD:65) kPa across top covers (p < 0.001) and was significantly higher for the 3 mm thick PPT than for four of the seven 6 mm thick top covers. Across 6 mm thick top covers, only two showed a significant peak pressure difference between them. Over time, peak pressures changed non-significantly from -2.7 to +47.8 kPa across top cover conditions. Comfort ratings were 8.0 to 8.4 across top covers (p = 0.863). The 6 mm thick foams provided more pressure relief than the 3 mm thick foam during walking in high-risk people with diabetes. Between the 6 mm thick foams and over time, only small differences exist. The choice of which 6 mm thick insole top cover to use may be determined more by availability, durability, ease of use, costs, or hygienic properties than by superiority in pressure-relief capacity.

Effect of different inner pressures of air insoles and walking durations on plantar pressure time integral

Air insoles have provided insights for reducing the risk of diabetic foot ulcers (DFU). The pressure time integral (PTI) is an effective assessment that considers the time effect in various physical activities. We investigated the interactions between three different insole inner pressures (80, 160, and 240 mmHg) and two walking durations (10 and 20 min). The big toe (T1), first metatarsal head (M1), and second metatarsal head (M2) were investigated in 13 healthy participants. One-way analysis of variance (ANOVA) showed that the effects of each insole inner pressure significantly differed (P < 0.05) with a 10 min walking duration. The PTI values resulting from 80 mmHg in M2 (38.4 ± 3.8, P = 0.002) and 160 mmHg in M1 (44.3 ± 4.3, P = 0.027) were lower than those from 240 mmHg. Additionally, the paired t test showed that the effects of each walking duration were also considerably different at 160 mmHg. The PTI at 10 min was lower than that at 20 min in M1 (44.31 ± 4.31, P = 0.015) and M2 (47.14 ± 5.27, P = 0.047). Thus, we suggest that walking with a pressure of 160 mmHg for 10 min has a lower risk of DFU.

Effectiveness of offloading interventions for people with diabetes-related foot ulcers: A systematic review and meta-analysis

BACKGROUND

Offloading treatment is crucial to heal diabetes-related foot ulcers (DFU). This systematic review aimed to assess the effectiveness of offloading interventions for people with DFU.

METHODS

We searched PubMed, EMBASE, Cochrane databases, and trials registries for all studies relating to offloading interventions in people with DFU to address 14 clinical question comparisons. Outcomes included ulcers healed, plantar pressure, weight-bearing activity, adherence, new lesions, falls, infections, amputations, quality of life, costs, cost-effectiveness, balance, and sustained healing. Included controlled studies were independently assessed for risk of bias and had key data extracted. Meta-analyses were performed when outcome data from studies could be pooled. Evidence statements were developed using the GRADE approach when outcome data existed.

RESULTS

From 19,923 studies screened, 194 eligible studies were identified (47 controlled, 147 non-controlled), 35 meta-analyses performed, and 128 evidence statements developed. We found non-removable offloading devices likely increase ulcers healed compared to removable offloading devices (risk ratio [RR] 1.24, 95% CI 1.09-1.41; N = 14, n = 1083), and may increase adherence, cost-effectiveness and decrease infections, but may increase new lesions. Removable knee-high offloading devices may make little difference to ulcers healed compared to removable ankle-high offloading devices (RR 1.00, 0.86-1.16; N = 6, n = 439), but may decrease plantar pressure and adherence. Any offloading device may increase ulcers healed (RR 1.39, 0.89-2.18; N = 5, n = 235) and cost-effectiveness compared to therapeutic footwear and may decrease plantar pressure and infections. Digital flexor tenotomies with offloading devices likely increase ulcers healed (RR 2.43, 1.05-5.59; N = 1, n = 16) and sustained healing compared to devices alone, and may decrease plantar pressure and infections, but may increase new transfer lesions. Achilles tendon lengthening with offloading devices likely increase ulcers healed (RR 1.10, 0.97-1.27; N = 1, n = 64) and sustained healing compared to devices alone, but likely increase new heel ulcers.

CONCLUSIONS

Non-removable offloading devices are likely superior to all other offloading interventions to heal most plantar DFU. Digital flexor tenotomies and Achilles tendon lengthening in combination with offloading devices are likely superior for some specific plantar DFU locations. Otherwise, any offloading device is probably superior to therapeutic footwear and other non-surgical offloading interventions to heal most plantar DFU. However, all these interventions have low-to-moderate certainty of evidence supporting their outcomes and more high-quality trials are needed to improve our certainty for the effectiveness of most offloading interventions.

Prevention of foot ulcers in persons with diabetes at risk of ulceration: A systematic review and meta-analysis

AIMS

Prevention of foot ulcers in persons with diabetes is important to help reduce the substantial burden on both individual and health resources. A comprehensive analysis of reported interventions is needed to better inform healthcare professionals about effective prevention. The aim of this systematic review and meta-analysis is to assess the effectiveness of interventions to prevent foot ulcers in persons with diabetes who are at risk thereof.

MATERIALS AND METHODS

We searched the available scientific literature in PubMed, EMBASE, CINAHL, Cochrane databases and trial registries for original research studies on preventative interventions. Both controlled and non-controlled studies were eligible for selection. Two independent reviewers assessed risk of bias of controlled studies and extracted data. A meta-analysis (using Mantel-Haenszel's statistical method and random effect models) was done when >1 RCT was available that met our criteria. Evidence statements, including the certainty of evidence, were formulated according to GRADE.

RESULTS

From the 19,349 records screened, 40 controlled studies (of which 33 were Randomised Controlled Trials [RCTs]) and 103 non-controlled studies were included. We found moderate certainty evidence that temperature monitoring (5 RCTs; risk ratio [RR]: 0.51; 95% CI: 0.31-0.84) and pressure-optimised therapeutic footwear or insoles (2 RCTs; RR: 0.62; 95% CI: 0.26-1.47) likely reduce the risk of plantar foot ulcer recurrence in people with diabetes at high risk. Further, we found low certainty evidence that structured education (5 RCTs; RR: 0.66; 95% CI: 0.37-1.19), therapeutic footwear (3 RCTs; RR: 0.53; 95% CI: 0.24-1.17), flexor tenotomy (1 RCT, 7 non-controlled studies, no meta-analysis), and integrated care (3 RCTs; RR: 0.78; 95% CI: 0.58-1.06) may reduce the risk of foot ulceration in people with diabetes at risk for foot ulceration.

CONCLUSIONS

Various interventions for persons with diabetes at risk for foot ulceration with evidence of effectiveness are available, including temperature monitoring (pressure-optimised) therapeutic footwear, structured education, flexor tenotomy, and integrated foot care. With hardly any new intervention studies published in recent years, more effort to produce high-quality RCTs is urgently needed to further improve the evidence base. This is especially relevant for educational and psychological interventions, for integrated care approaches for persons at high risk of ulceration, and for interventions specifically targeting persons at low-to-moderate risk of ulceration.

Offloading and adherence through technological advancements: Modern approaches for better foot care in diabetes

OBJECTIVE

This manuscript aims to provide a review and synthesis of contemporary advancements in footwear, sensor technology for remote monitoring, and digital health, with a focus on improving offloading and measuring and enhancing adherence to offloading in diabetic foot care.

METHODS

A narrative literature review was conducted by sourcing peer-reviewed articles, clinical studies, and technological innovations. This paper includes a review of various strategies, from specifically designed footwear, smart insoles and boots to using digital health interventions, which aim to offload plantar pressure and help prevent and manage wounds more effectively by improving the adherence to such offloading.

RESULTS

In-house specially made footwear, sensor technologies remotely measuring pressure and weight-bearing activity, exemplified for example, through applications like smart insoles and SmartBoot, and other digital health technologies, show promise in improving offloading and changing patient behaviour towards improving adherence to offloading and facilitating personalised care. This paper introduces the concept of gamification and emotive visual indicators as novel methods to enhance patient engagement. It further discusses the transformative role of digital health technologies in the modern era.

CONCLUSIONS

The integration of technology with footwear and offloading devices offers unparallelled opportunities for improving diabetic foot disease management not only through better offloading but also through improved adherence to offloading. These advancements allow healthcare providers to personalise treatment plans more effectively, thereby promising a major improvement in patient outcomes in diabetic foot ulcer healing and prevention.

Effective and clinically relevant optimisation of cushioning stiffness to maximise the offloading capacity of diabetic footwear

INTRODUCTION

Optimising the cushioning stiffness of diabetic footwear/orthoses can significantly enhance their offloading capacity. This study explores whether optimum cushioning stiffness can be predicted using simple demographic and anthropometric parameters.

METHODS

Sixty-nine adults with diabetes and loss of protective sensation in their feet were recruited for this cross-sectional observational study. In-shoe plantar pressure was measured using Pedar® for a neutral diabetic shoe (baseline) and after adding cushioning footbeds of varying stiffness. The cushioning stiffness that achieved maximum offloading was identified for each participant. The link between optimum cushioning stiffness and plantar loading or demographic/anthropometric parameters was assessed using multinomial regression.

RESULTS

People with higher baseline plantar loading required stiffer cushioning materials for maximum offloading. Using sex, age, weight, height, and shoe-size as covariates correctly predicted the cushioning stiffness that minimised peak pressure across the entire foot, or specifically in the metatarsal heads, midfoot and heel regions in 70%, 72%, 83% and 66% of participants respectively.

CONCLUSIONS

Increased plantar loading is associated with the need for stiffer cushioning materials for maximum offloading. Patient-specific optimum cushioning stiffness can be predicted using five simple demographic/anthropometric parameters. These results open the way for methods to optimise cushioning stiffness as part of clinical practice.

Neuropathic foot ulcers in the tallest patients with acromegalic gigantism: a common and significant problem. Historical overview

PURPOSE

We present a historical overview on neuropathic ulcers in patients with acromegalic gigantism.

MATERIALS AND METHODS

The case histories of 6 famous patients with acromegalic gigantism and living in the twentieth century were analyzed. The combined final height and maximum weight of these giants were: 272 cm. & 215.9 kg., 218.4 cm. & 125 kg., 242 cm. & 165 kg., 220.5 cm. & 135 kg., 235 cm. & 136 kg. and 224.8 cm. & 174 kg.

CONCLUSIONS

Neuropathic foot ulcers leading to hospital admissions and surgical and medical interventions were reported in 6 patients with acromegalic gigantism. These ulcers significantly impaired the daily activities of these individuals. Neuropathies of the sural nerve in patients with acromegalic gigantism can lead to hypoesthesia and hypoalgesia of the lower legs and feet. Potential contributing factors for the development of neuropathic ulcers of the feet in patients with acromegalic gigantism and neuropathy might be leg and foot deformities, muscle weakness and poor quality footwear. Diabetes mellitus, or impaired glucose intolerance does not necessarily seem to play a role.

The influence of running shoe with different carbon-fiber plate designs on internal foot mechanics: A pilot computational analysis

A carbon-fiber plate (CFP) embedded into running shoes is a commonly applied method to improve running economy, but little is known in regard the effects of CFP design features on internal foot mechanics. This study aimed to explore how systematic changes in CFP geometrical variations (i.e., thickness and location) can alter plantar pressure and strain under the forefoot as well as metatarsal stress state through computational simulations. A foot-shoe finite element (FE) model was built and different CFP features including three thicknesses (1 mm, 2 mm, and 3 mm) and three placements (high-loaded (just below the insole), mid-loaded (in between the midsole), and low-loaded (just above the outsole)) were further modulated within the shoe sole. Simulations were conducted at the impact peak instant during forefoot strike running. Compared with the no-CFP shoe, peak plantar pressure and compressive strain under the forefoot consistently decreased when the CFP thickness increased, and the low-loaded conditions were found more effective (peak pressure decreased up to 31.91% and compressive strain decreased up to 18.61%). In terms of metatarsal stress, CFP designs resulted in varied effects and were dependent on their locations. Specifically, high-loaded CFP led to relatively higher peak metatarsal stress without the reduction trend as thickness increased (peak stress increased up to 12.91%), while low-loaded conditions showed a gradual reduction in peak stress, decreasing by 0.74%. Therefore, a low-loaded thicker CFP should be considered to achieve the pressure-relief effects of running shoes without the expense of increased metatarsal stress.

Nonoperative Treatment of Charcot Neuro-osteoarthropathy

Conservative treatment of Charcot neuro-osteoarthropathy (CN) aims to retain a stable, plantigrade, and ulcer-free foot, or to prevent progression of an already existing deformity. CN is treated with offloading in a total contact cast as long as CN activity is present. Transition to inactive CN is monitored by the resolution of clinical activity signs and by resolution of bony edema in MRI. Fitting of orthopedic depth insoles, orthopedic shoes, or ankle-foot orthosis should follow immediately after offloading has ended to prevent CN reactivation or ulcer development.

Footwear comfort: a systematic search and narrative synthesis of the literature

OBJECTIVE

To provide a narrative synthesis of the research literature pertaining to footwear comfort, including definitions, measurement scales, footwear design features, and physiological and psychological factors.

METHODS

A systematic search was conducted which yielded 101 manuscripts. The most relevant manuscripts were selected based on the predetermined subheadings of the review (definitions, measurement scales, footwear design features, and physiological and psychological factors). A narrative synthesis of the findings of the included studies was undertaken.

RESULTS

The available evidence is highly fragmented and incorporates a wide range of study designs, participants, and assessment approaches, making it challenging to draw strong conclusions or implications for clinical practice. However, it can be broadly concluded that (i) simple visual analog scales may provide a reliable overall assessment of comfort, (ii) well-fitted, lightweight shoes with soft midsoles and curved rocker-soles are generally perceived to be most comfortable, and (iii) the influence of sole flexibility, shoe microclimate and insoles is less clear and likely to be more specific to the population, setting and task being performed.

CONCLUSION

Footwear comfort is a complex and multifaceted concept that is influenced not only by structural and functional aspects of shoe design, but also task requirements and anatomical and physiological differences between individuals. Further research is required to delineate the contribution of specific shoe features more clearly, and to better understand the interaction between footwear features and individual physiological attributes.